1. Field of the Invention
The present invention relates to an image processor and an image processing method that restore a superimposed image state of a multiple image in which acquired images of a subject are superimposed on each other, an image acquisition apparatus including the image processor, and a storage medium storing an image processing program allowing a computer to function as such an image processor.
It should be noted that a “multiple image” in this specification represents general images in which images of a subject are superimposed on each other. Specifically, it represents: an image acquired when an image acquisition apparatus forms images of a subject in a superimposed manner; a ghost image in which images of a subject are superimposed because of an electronic or an optical function; a flare image; an image in which images of a subject are multiply-layered because of a failure in positioning processing when a plurality of images are positioned and superimposed on each other; and others. Further, “multiple” means a state where images are at least partially superimposed on each other.
2. Description of the Related Art
There is proposed a technology that includes a mechanism that acquires images of a subject in a superimposed manner in an image acquiring apparatus such as a camera, acquires images of the subject in the form of a multiple image, and measures a displacement between superimposed images in the multiple image to measure a distance to the subject when acquiring the image by the image acquisition apparatus. For example, Jpn. Pat. Appln. KOKAI Publication No. 2006-329897 discloses a technique that uses double image reflected on a transparent plate to measure a distance. Jpn. Pat. Appln. KOKAI Publication No. 7-135597 discloses a technique that acquires a double image by utilizing a diaphragm having a plurality of apertures to acquire a double image to measure a distance.
In a conventional example, when removing ghosting in a ghost image wherein images in a television program appear in a superimposed manner because of the influence of reflection of electromagnetic waves by buildings and other structures, a ghost canceling technique using, e.g., a ghost canceling reference signal (GCR signal) has been adopted as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2000-156799.
When acquiring an image by using an image acquisition apparatus such as a camera, there is known multiple image generation due to a flare phenomenon that backlight or strong light provokes reflection/scattering on or in a lens surface. To avoid such a phenomenon, an ingenuity, e.g., attaching a lens hood to a periphery of a camera lens is executed.
In the conventional example, when a plurality of images are positioned and the plurality of images are superimposed on each other, a multiple image may be produced from the superimposed images because of a failure in positioning. In such a case, processing of blurring a part between the superimposed images to correct the image is carried out.